1. Field of Invention
The present invention relates to a process for producing pyripyropene derivatives useful as pest control agents and more specifically relates to a process for producing pyripyropene derivatives that have acyloxy groups at the 1- and 11-positions and a hydroxyl group at the 7-position thereof.
2. Background Art
Pyripyropene derivatives having acyloxy at 1- and 11-positions and hydroxyl at the 7-position thereof are compounds that have control effects against pests, as described in WO 2006/129714.
WO 2006/129714 and Japanese Patent Application Laid-Open No. 259569/1996 disclose a process for producing pyripyropene derivatives having acyloxy at 1- and 11-positions and hydroxyl at the 7-position thereof. According to the production process, the pyripyropene derivatives are purified or isolated from a plurality of products produced by nonselective hydrolysis of acyloxy using a 1,7,11-triacyloxy compound as a starting compound. This production process, however, suffers from problems such as low yield and unsuitability for quantity synthesis.
Further, Japanese Patent Application Laid-Open No. 259569/1996 describes the use of a combination of protective groups for the synthesis of pyripyropene derivatives, and Journal of Antibiotics Vol. 49, No. 11, p. 1149, 1996, Bioorganic Medicinal Chemistry Letter Vol. 5, No. 22, p. 2683, 1995, Japanese Patent Application Laid-Open No. 269065/1996, and WO 2008/013336 disclose a synthesis example that introduces acyl into the 7-position by utilizing a protective group. These documents, however, do not disclose a specific process that utilizes a protective group in the production of pyripyropene derivatives that have acyloxy at the 1- and 11-positions and hydroxyl at the 7-position thereof.